From U.S. Pat. No. 4,794,696, it is known to arrange window like openings in the solid material of a guide bar to reduce weight and to again cover these openings with cover plates fixed on the main member of the guide bar to maintain bending stiffness. It has been shown in practice that such guide bars have a stiffness and especially a torsion stiffness which is adequate for working with a motor chain saw up to a predetermined length with a significant weight reduction.
For exceptionally high loads of the guide bar or for guide bars which are configured to be extremely long, it has however been determined that the window-like openings provided for weight reduction cannot be configured to have any desired size since then a reduction of the torsion stiffness must be considered.